Enhanced fuel and method of producing enhanced fuel for operating internal combustion engine

ABSTRACT

An enhanced fuel, a method of producing such enhanced fuel, and method of using such enhanced fuel for operating internal combustion engine. The fuel includes a mixture of at least one alcohol, water and ammonium nitrate (AN) as a cetane enhancer. The water is included in a quantity which renders the ammonium nitrate dissolved in the at least one alcohol. The fuel further contains dimethylether as an ignition-improver additive, at least one lubricity agent and at least one anti-corrosion agent.

TECHNICAL FIELD

The present disclosure relates to enhanced fuels suitable for use ininternal combustion engines. Moreover, the present disclosure is alsoconcerned with methods of producing such enhanced fuels. Furthermore,the present disclosure is also concerned with a method of using suchfuel for operating an internal combustion engine.

BACKGROUND

The use of combustible hydrocarbon fuels in combustion systems, such asinternal combustion engines, is well known. Typically, combustiblehydrocarbon fuels includes, petrol fuel (gasoline) or diesel fuel, whichare oxidized by air to generate hot gases that are used to generatemechanical power, for example for vehicles powered by spark-ignitionengines or compression-ignition engines. However, such combustion in airgenerates as by-products carbonaceous soot particles and Nitrogen oxides(NOx). Several innovations have been devised in recent years to reduceand/or filter such soot particles and Nitrogen oxides (NOx) in exhaustgases generated in operation from combustion systems.

Generally, such combustion fuels are derived, namely manufactured, fromgeological fossil reserves. Further, such fossil reserves are of finitecapacity and are being gradually exhausted, as the present Worldconsumption of oil and gas is in an order of 100 million barrels of oilequivalent per annum. More recently, there is a growing interest inbiofuels derived from contemporary biota, and therefore potentially moresustainable. The use of biofuel as a motor fuel has been already studiedin detail since the 20th Century. Biofuels, in contradistinction toconventional fossil-reserve-derived fuels, are used as a motor fuel, oran addition to basic fossil-reserve-derived fuel, in many countries,such as Brazil, Germany, Sweden and USA [1]. Technologies have beendeveloped for producing motor fuels including plain ethanol, as well asits blends with regular gasoline and diesel fuel to be used in internalcombustion engines. Significant innovations relating to alternativefuels are described in published patent documents WO2009/106647, U.S.Pat. No. 5,628,805 and DE10339355.

Further, in a European patent document EPO1 1 6197B1 (proprietor: AECILtd.; inventor Stiff), there is described a fuel additive comprising amixture of a first component A, and second component B, wherein thefirst component A is at least one alcohol with a molecular weight ofless than 160, and wherein the second component B is at least oneorganic compound of the formula:

NO₂—O—(CH₂CH₂—O—)x-NO₂   Eq. 1

wherein x is an integer greater than 3, and wherein the averagemolecular weight of at least one compound of the formula described inEquation 1 (Eq. 1) is in a range of 260 to about 390, with a provisothat no other compounds of formula described in Equation 1 are present.

Optionally, the fuel additive is added to a fuel such as ethanol and/ormethanol to provide a mixture which can be combusted in combustionengines, for example in cylinder-based internal combustion engines. Theadditive is capable of improving fuel ignition in cylinder-basedinternal combustion engines, for example at lower temperatures when suchengines are started and their respective engine blocks are cold.

Over recent years, many different fuel additives have been developed. Anexample of a contemporary fuel additive is known as “Avocet”, “Avocef isa trademark.

In the mid-1980's, a South African chemicals group, AECI, introduced a“green innovation” in the area of fuels, namely “Encetal”; “Enceta\” isa trademark. Encetal was developed for purposes of seeking to increase alocal consumption of methanol produced from local coal feedstock, whichcould be used as an alternative to imported oil for fuels.

“Encetal, the name of the fuel mixture of Methanol and Avocet, burnscleanly, producing low amounts of pollutant gases (Nitrous Oxide andCarbon Monoxide) and particulates in a vehicle's exhaust. Moreover,Avocet is an ignition improver to allow methanol fuel to be used indiesel engines, requiring a minimum of engine modifications toaccommodate its use.

Avocet has been employed in several tests using alcohols as biofuels, tosubstitute for fossil-reserve-derived diesel fuel in private and publictransportation vehicles. In the mid-1990s, ethanol containing Avocet ata concentration in a range of 2% to 10% by volume as an ignitionenhancer was tested in a small controlled group of public transportvehicles [1]. Theory predicts a significantly higher volume consumptionof ethanol, in comparison to diesel fuel, but the exact higher volumehas to be calculated for each case, since it depends on the specificcharacteristics of the vehicle (e.g. operating temperature) and thedetailed composition of the fuel itself. It was found from the teststhat the use of ethanol-Avocet fuel consumed 84% more per volume, whichboth negatively compensated for an initial economic argument as well aspresented a new significant logistic challenge of transporting 84% morefuel by volume.

Moreover, the use of alcohols in existing diesel engines also requiressome modifications to be made to engine components to prevent chemicaldegradation due to exposure to alcohols. Further improvements in engineoperation, temperature and catalysts are needed in preparation for theuse of ethanol and other alcohols as a replacement for diesel fuel. Asfar as economic arguments are concerned, a reduction in the use ofAvocet, which represents a significant proportion of the costs,potentially makes combustion systems cheaper, namely potentiallysufficiently cheaper to compensate for the comparative ratioAlcohol/diesel; as above, ethanol is taken as the reference,ethanol/diesel=1.84.

An initial economic argument for using the Avocet-enhanced methanol fuelas a diesel replacement was based on an average 25% cost savings whencomparing the same volume of methanol to diesel fuel. Meanwhile,environmental arguments pointed out less particulate emissions and lesssmokiness of such Avocet-enhanced methanol fuel. However, in the early1990's, the use of Avocet as an ignition improver or as a fuel enhancerwas been deemed impracticable and/or too expensive for regularautomobiles and other road vehicles by the parent company ICI-UK(Imperial Chemical Industries UK was the holding company of the groupthat owned AECI). This conclusion was reached, in part, due to the lackof commercial drive for environmentally friendly fuels, when theadditive has been introduced in the early 1980s.

Although the composition of Avocet is proprietary, and may have variedover time, the composition of the original Avocet additive includesfollowing components as provided in Table 1:

TABLE 1 Original Avocet composition Component part Percentagecomposition PEG (PolyEthyleneGlycol) dinitrate Circa 75% to 90% MethanolCirca 10% to 25% Lubricity additive 1.5% Antioxidant 0.1%

However, as aforementioned, Avocet is prohibitively expensive for use inmany contemporary combustion systems, which has unfortunately limitedits general use.

Further, additives are also employed in exhaust systems of vehicles, forexample for reducing emissions of NOx components in exhaust gasesemitted from exhaust systems associated with internal combustionengines. A well-known contemporary additive for this purpose of reducingNOx emissions is “AdBlue”, which is the registered trademark for AUS32,or Aqueous Urea Solution 32.5% that is used with the Selective CatalyticReduction system (SCR) to reduce emissions of oxides of Nitrogen fromthe exhaust of UK diesel vehicles. AdBlue is a 32.5% solution ofhigh-purity urea in de-mineralized water that is clear, non-toxic andsafe to handle. It is non-explosive, non-flammable, nor harmful to theenvironment. AdBlue is classified under a minimum risk category oftransportable fluids. However, Adblue is not a fuel, nor a fueladditive, and needs to be supplied from a dedicated tank in heavy-dutyvehicles, for example trucks and buses. The dedicated tank isreplenished with

AdBlue in a similar manner to refueling diesel into heavy-duty vehicles.

However, as aforementioned, Avocet is a fuel additive and isprohibitively expensive for use in many contemporary combustion systems,which has unfortunately limited its general use. Therefore, there is aneed for alternative additives which, when added to fuel, are able toenhance combustion properties of the fuel.

In an example, a patent document WO2012021 64A1 discloses use ofadditives in conjunction with diesel fuel. The document mentionsAmmonium Nitrate (AN) as an example of compounds to be potentially usedas an additive to diesel. In this case, AN is described as beingemulsified in diesel. However, such emulsified fuels may be unstable ina range of temperature conditions in which the engine may need tooperate, and hence such a fuel may be considered to be unreliable inparticular operating conditions. Further, there is no mention of its useas a cetane enhancement of employed AN in methanol.

Further, currently accepted knowledge is that an additive based in PEGdinitrate is the only proven ignition improver for alcohols. In suchinstance, an alcohol based fuel may possibly use PEG dinitrate as theignition improver. Accordingly, there arises a need to appropriately usesuch alcohol based fuel (having PEG dinitrate as ignition improver), andany improvement in combustion engines which are operable to burn suchalcohol based fuel.

Therefore, in light of the foregoing discussion, there exists a need toovercome the aforementioned drawbacks of conventional fuels(particularly alcohol based fuels) and their use.

SUMMARY

The present disclosure seeks to provide an enhanced fuel for use ininternal combustion engines, for example the enhanced fuel which isbased upon methanol.

Also, the present disclosure seeks to provide additives for fuels,which, when added to the fuels, is capable of enhancing the fuels.

Further, the present disclosure also seeks to provide a method ofproducing such enhanced fuel.

Moreover, the present disclosure also seeks to provide a method of usingsuch enhanced fuel for operating internal combustion engine.

According to an aspect, there is provided a fuel for use in internalcombustion engines, wherein the fuel includes a mixture of at least onealcohol, water and ammonium nitrate (AN) as a cetane enhancer. The wateris included in a quantity which renders the ammonium nitrate dissolvedin the at least one alcohol, wherein the at least one alcohol includesmethanol.

Optionally, the AN and water solution is mixed in alcohol to allow theAN/alcohol ratio in be in a range of 0.5% to 20% by weight with respectto the alcohol, wherein the AN is included in a concentration having arange of 1% to 5% by weight with respect to the alcohol.

Optionally, the fuel further contains polyethylene glycol dinitrate(PEGDN), wherein the PEGDN is included in a concentration in a range of5% to 10% by weight with respect to alcohol.

Optionally, the fuel further contains at least one ignition-improveradditive, at least one lubricity agent and at least one anti-corrosionagent, wherein the ignition-improver additive is at least one ofdimethylether (DME), diethyl ether or methyl ethyl ether, wherein theDME is included in a concentration in a range of 0.1% to 3% by weightwith respect to the alcohol.

Optionally, the lubricity agent is at least one of polyethylene glycol,synthetic esters, and fatty acids, wherein the anti-corrosion agentcontains organic amines.

According to another aspect, there is provided a method of producing afuel, wherein the method includes:

(i) Mixing at least one alcohol, dimethylether (DME) and AmmoniumNitrate (AN); and

-   (ii) During mixing in (i), adding water in a quantity which renders    the AN dissolved in the at least one alcohol,-   wherein the at least one alcohol includes methanol.

Optionally, the method further includes adding at least one lubricityagent and at least one anti-corrosion agent.

Optionally, the method further includes adding polyethylene glycoldinitrate (PEGDN).

According to yet another aspect, there is provided a method of using afuel for operating an internal combustion engine, wherein the combustionengine including one or more combustion chambers having reciprocatingand/or rotating elements therein which are operable to generatemechanical work from the engine, and an injection arrangement forinjecting fuel into the one or more combustion chambers, wherein themethod includes:

-   (a) operating the injection arrangement to inject an alcohol -based    fuel into the one or more combustion chambers, and wherein there is    injected in combination with the alcohol-based fuel at least one    ignition-improver.

Optionally, the method further includes pre-mixing the alcohol-basedfuel and the at least one ignition-improver using a pre-mixingarrangement.

Optionally, the method further includes injecting the pre-mixedalcohol-based fuel and at least one ignition-improver as aqueoussolution into one or more engine cylinders by a common injector.

Optionally, the method further includes injecting the alcohol-based fueland the at least one ignition-improver into one or more engine cylindersby separate injectors.

Optionally, the method further includes controlling an amount of the atleast one ignition-improver injected into the one or more combustionchambers relative to an amount of alcohol-based fuel injected therein byusing a control arrangement.

More optionally, the controlling of the amount of the at least oneignition-improver is based on one or more measured parameters associatedwith the combustion engine.

Optionally, the alcohol-based fuel contains at least one alcohol, water,at least one lubricity agent and at least one anti-corrosion agent,wherein the anti-corrosion agent contains organic amines.

Optionally, the ignition-improver is at least one of: Dimethylether(DME), diethyl ether, methyl ethyl ether, Ammonium Nitrate (AN),PEG-nitrate, octyl nitrate, hydrazine, and hydroxylamine nitrate.

The present disclosure relates to an enhanced fuel, a method ofproducing such enhanced fuel, and method of using such enhanced fuel foroperating internal combustion engine. Specifically, the presentdisclosure relates to fuels, for example to hydrocarbon fuels which areuseable as a replacement for conventional diesel fuel and petrol fuels.The fuel is of advantage is that an addition of water renders AmmoniumNitrate co-soluble in at least one alcohol, for example methanol,thereby providing a solution which is stable in storage, and alsouseable directly as a substitute for fuels such as diesel, petrol,kerosene and other heavy fuel oils. Further, addition of water keeps theengine cool, on account of the high latent heat of evaporation of water,thereby decreasing the need for cooling systems. Furthermore, the fuelof the present disclosure is economical to manufacture and results in aclean burn reaction within combustion engines. For example, all fuelcomponents are inexpensive and widely available, which enables largescale production for allowing easy adaptation in the market andefficient distribution. Moreover, the fuel is capable of being employedas a substitute fuel in various types of engine systems, although ratiosof its constituent components are optionally varied depending uponintended uses.

It will be appreciated that features of the disclosure are susceptibleto being combined in various combinations without departing from thescope of the disclosure as defined by the appended claims.

DESCRIPTION OF THE DIAGRAMS

Embodiments of the present disclosure will now be described, by way ofexample only, with reference to the following diagrams wherein:

FIG. 1 is a graphical illustration of an enhanced fuel, in accordancewith an embodiment of the present disclosure;

FIG. 2 is a graphical illustration of an enhanced fuel, in accordancewith another embodiment of the present disclosure;

FIG. 3 is an illustration of a method of producing an enhanced fuel, inaccordance with an embodiment of the present disclosure;

FIG. 4 is an illustration of components of a enhanced fuel applied to aspark-ignited engine, in accordance with an embodiment of the presentdisclosure; and

FIG. 5 is an illustration of components of a enhanced fuel applied to acompression-ignition engine, in accordance with an embodiment of thepresent disclosure.

In the accompanying diagrams, when a number is non-underlined andaccompanied by an associated arrow or lead line, the non-underlinednumber is used to identify a general item at which the arrow or leadline is pointing.

DESCRIPTION OF EMBODIMENTS OF THE DISCLOSURE

In overview, the present disclosure is concerned with an enhanced fuelwhich is based upon an alcohol, for example ethanol and/or methanol,which is economical in use, and which can be used as a diesel fuelsubstitute, with only minor changes being necessary to an internalcombustion engine which is configured to operate from conventionaldiesel fuel.

The environmental benefits of using an alcohol, as a replacement fordiesel fuel, have been well established in prior-art, since a combustionsystem employing such alcohol as a fuel produces lower amounts ofpollutant gases and particulates in a vehicle's exhaust in comparison tofuels such as petrol and diesel fuel. Moreover, in recent years,governments and society in general have been increasingly applyingpressure on companies to adopt more environmentally friendlyalternatives. Therefore, as the intrinsic environmental benefits ofusing alcohols as a running fuel of contemporary vehicles arewell-accepted and understood, it is clear from the foregoing thatimproving the economic efficiency of the use of alcohols as alternativefuels is a key problem to be resolved.

In the present disclosure, there is proposed an alternative additive asa substitute for Avocet additive that allows alcohols to be used inexisting compression ignition engines.

Ammonium Nitrate is known to be an explosive material. Moreover,Ammonium Nitrate has been hitherto perceived to be unsuitable for use asan additive, because it is not soluble in alcohols, for examplemethanol. However, pursuant to embodiments of the present disclosure,Ammonium nitrate (AN) has a significant potential as a cetane enhancerfor alcohols, such as methanol. The cetane enhancement capabilityeffectively allows AN to be used as an ignition improver for suchalcohol fuels. Ammonium Nitrate is, for example, manufactured in largequantities, for example for use in agriculture to replenish soil aftercrops have been grown which have a high fixed nitrogen requirement, forexample grain crops, beans and so forth.

In respect of the use of ammonium nitrate (AN) as additive for methanol,Ammonium nitrate (AN) has a significant potential as a cetane enhancerfor alcohols such as methanol, as aforementioned. The cetane enhancementcapability effectively allows AN to be used as an ignition improver forsuch alcohol fuels, which allows these fuels to be used as directreplacement for known convention combustible fuels.

Disclosed an embodiment of the present disclosure in which AN isemployed as an ignition improver/cetane enhancement for methanol, oranother alcohol. AN is not very soluble in methanol for example, butboth methanol and AN are soluble in water. Therefore, there is discloseda fuel including a mixture of an alcohol, for example ethanol and/ormethanol, AN and water, as shown in FIG. 1. Such a fuel is beneficiallymanufactured from a method including:

-   (i) Mixing methanol and AN to the desired concentration, for example    in a range of 0.5% to 10% AN relative to methanol; and-   (ii) During mixing in (i), adding enough water so that AN becomes    dissolvable in the methanol water mix.

In step (i) of the method, the range in which AN needs to be added isdefined by a ratio N/C (namely, Nitrogen to Carbon), wherein Nitrogenatoms come from the AN additive and Carbon atoms, mostly, comes from thefuel, for example methanol.

In an example, the AN is included in a concentration having a range of1% to 5% by weight with respect to the alcohol. Further, the AN andwater solution is mixed in alcohol to allow the AN/alcohol ratio in bein a range of 0.5% to 20% by weight with respect to the alcohol.

In step (ii) of the method, water needs to be added to an extent thatsolubilises the required amount of AN, namely:

Enhanced fuel=Methanol+water+AN   Eq. 2

The enhanced fuel (or mixture) of water, AN and methanol is of advantagein that it can be easily stored over a long-term period withoutseparating out into individual components parts, and does not form anemulsion and does not need to be emulsified. The enhance fuel pursuantto Equation 2 (Eq. 2) only contains fully soluble compounds and, thus,is considered to be more stable and more reliable in operatingconditions. The enhanced fuel pursuant to Equation 2 (Eq. 2) isconsiderably cheaper than known diesel fuel substitutes based onmethanol, for example employing Avocet, and also is very clean whenburnt in an internal combustion engine, for example very low sootproduction and low NOx production. Moreover, the enhanced fuel pursuantto Equation 2 (Eq. 2) potentially avoids a need to employ Adblue in theexhaust systems of vehicles.

Methanol can be generated from a variety of sources, for examplefermenting biological waste, biota material, algea culture, processingwood by-products, fossil fuel reserves, coal, coal liquefaction,hydrates and so forth; mutatis mutandis ethanol is similarly derivable.

Embodiments of the present disclosure are concerned with an introductionof a new additive which increases the efficiency of a given fuel, forexample methanol-based fuel, by acting as a cetane enhancer. The newadditive provides at least one of following benefits:

-   (a) the new additive allows methanol to act a direct replacement for    diesel fuel;-   (b) the new additive in solution is non-explosive, and thus less    hazardous in than, for example, octyl nitrate; and-   (c) the new additive has a potential for application in petrol    engines.

“Cetane” is a measure of an ignition quality of a diesel fuel. Thehigher the cetane measure of a given diesel fuel, the easier it is tostart a standard (direct injection) diesel engine using the given dieselfuel. The cetane measure is defined by a percentage, by volume, ofcetane, with a chemical name “hexadecane”’, in a combustion mixture,containing cetane and 1-methylnaphthalene, whose ignitioncharacteristics match those of a given diesel fuel being tested.Comparisons with other additives and fuels can be made by way of“equivalent cetane measure”, for example as employed when describingembodiments of the present disclosure.

Benefits of the enhanced fuel in Equation 2 (Eq. 2) include:

-   (a) The method allows Ammonium Nitrate to be used as an ignition    improver to methanol or similar alcohols, in turn allowing the fuel    to be used in existing diesel engines with minimum modifications;-   (b) The addition of water keeps an engine burning the fuel of    Equation 2 (Eq. 2) cool (due to a high latent heat of water),    thereby decreasing a need for cooling systems, thus making the    vehicle more energy efficient;-   (c) Lower particulate emission from engines burning the enhanced    fuel of Equation 2, namely lower particulate emission than    achievable by employing other methods, for example sing exhaust    filters, using Adblue spraying in exhaust systems and so forth; (d)    Environmentally friendly, since the N-groups in AN are released as    N2 gas at the end of a burn cycle in a combustion engine;-   (e) The enhanced fuel of Equation 2 (Eq. 2) results in a significant    reduction in cost in comparison to PEG-dinitrate-based additives,    namely AN cost approximately less than 1/10th of Avocet additives;    and-   (f) Cooler engine operation consequent upon the introduction of    water results in lower NOx formation. Since NOx is the precursor of    tropospheric ozone pollution, the reduction in NOx constitutes a    significant environmental benefit.

In an example, systems and methods may be disclosed for the use of anaqueous solution of ammonium nitrate (AN) as an ignition improverdirectly injected into the engine cylinder, which will be explained ingreater detail herein later. For example, the systems and methods mayinclude tanks fitted to contain an aqueous solution of urea as the tanksto contain the AN solution prior to injection.

According to another aspect, the enhanced fuel, as disclosed above withthe help of the FIG. 1 and Equation 2 (Eq. 2), can also include othercomponents that collectively form additive for the fuel.

In an example, the fuel further includes an ignition-improver additive,preferably, dimethylether (DME). Specifically, the fuel includes DME inaddition to the components of the fuel disclosed in FIG. 1. In suchinstance, ammonium nitrate (AN) acts cetane enhancer additive, which isan alternative additive as a substitute for Avocet additives that allowsalcohols to be used as an improved fuel in existing compression-ignitionengines. Optionally, the fuel can further include other cetane enhancer,such as hydrazine, hydroxylamine nitrates, octyl nitrate having similartechnical benefits, although their cost is greater than that of AN.

Dimethylether (DME) and other compounds with relatively high vapourpressures, including low-boiling point ethers, namely diethyl ether ormethyl ethyl ether are suitable compounds to be employed asignition-improver additive, particularly to enhance the cold-start ofspark-ignited engines.

Dimethylether (DME) is produced by dehydration of methanol over apreferred catalyst, and is an additive independent of petroleum. Forexample, DME is soluble in methanol and water, and thus preferably mixeddirectly into the fuel without the need of emulsification. The chemicalformula of DME does not contain Carbon-Carbon bonds, which significantlyreduces the possibility of formation of particulate impurities whencompared to other commonly used additives, for example Avocet. Furtheradvantages include the possibility of using DME in any engine tuned tobe run with methanol as a fuel, wherein no extra modifications in thistype of engine are needed.

Dimethylether (DME) additive is inexpensive and readily available inlarge-scale. It provides several benefits to the engine operation, whichincludes enhancing the cold-start of spark-ignited engines. The DMEadditive can be utilised in range of 0.1-5% by weight with respect tothe alcohol. For example, the DME additive is to be utilised range of0.1-3% by weight with respect to the alcohol. For its utilisation as anadditive to a methanol-based fuel, DME has the following favourablecharacteristics:

-   a) It is inexpensive, widely available and in large scale    production.-   b) It is miscible with methanol.-   c) It is derived efficiently from methanol by dehydration over an    alumina catalyst, and, as such, is independent of petroleum.-   d) It is a chemical with no C—C bonds, thus significantly decreasing    the chance of formation of particulate impurities.-   e) Engines tuned to be run with methanol-based fuels are also    capable of running with DME as an additive without extra    modifications.-   f) It has a high vapour pressure at ambient temperatures, so    enabling facile starting of alcohol fuelled SI engines.

Methanol modified in the way proposed in the present disclosure enablesthe full benefits of dedicated methanol SI engines to be realised. Thesebenefits include low emissions coupled with the high fuel efficiency andhigh power output resulting from increased compression ratios madepossible by methanol's high octane value.

There is therefore disclosed an embodiment of the present disclosure,wherein DEM and/or AN are/is employed as ignition improver for methanoland/or another alcohol. AN is not directly soluble in methanol, forexample, but both methanol and AN are soluble in water. Therefore, thereis disclosed a fuel including a mixture of an alcohol, for exampleethanol and/or methanol, water, DME (as ignition-improver additive) andAN (as cetane enhancer), as shown in FIG. 2. It is to be understood thatAN may be optionally added as cetane enhancer. Such a fuel isbeneficially optionally manufactured using a method (300 shown in FIG.3). Specifically, the method 300 of producing a fuel includes:

-   (i) Mixing methanol, DME and AN to a desired concentration, for    example in a range of 1% to 5% AN relative to methanol; and 0.1 to    3% DME relative to methanol, at step 302;-   (ii) During mixing in (i), adding enough water so that AN becomes    dissolvable in the methanol-water-DME mix, at step 304.

In step (i) of the method, the range in which AN needs to be added isdefined by a ratio N/C (namely, Nitrogen to Carbon), wherein Nitrogenatoms come from the AN additive and Carbon atoms, mostly, comes from thefuel, for example methanol. In contradistinction, in a case of PEGdinitrate, there is a Nitrogen to Carbon N:C=20:1 is a typicallyrequired ratio. However, the values may vary depending on requirementsof engine design and operating temperature.

In step (ii) of the method, water needs to be added to an extent thatrenders the required amount of AN soluble in the mixture, namely:

Enhanced fuel=Methanol+water+DME+AN   Eq. 3

Such a mixture of water, AN and methanol is of advantage in that it canbe easily stored over a long-term period without separating out intoindividual component parts, and does not form an emulsion and does notneed to be emulsified.

The enhanced fuel pursuant to Equation 3 is considerably cheaper thanknown fuel substitutes based upon methanol, for example employingAvocet, and also is very clean when burnt in an internal combustionengine, for example results in very low soot production and low NOxproduction. Moreover, the enhanced fuel pursuant to Equation 3potentially avoids a need to employ Adblue in exhaust systems ofvehicles.

Additionally, the fuel (or the method 300) also includes addition of atleast one lubricity agent and at least one anti-corrosion agent, soproviding a “universal fuel” (which is alcohol based). Therefore, fuelof the present disclosure, proposes an alcohol-based fuel which can beused in vehicles powered by compression-ignition (diesel family),spark-ignition engines, or other suitable hybrid engines.

For example, the method 300 (or the fuel) further includes adding anignition-improver additive, preferably dimethylether (DME), adding atleast one lubricity agent and at least one anti-corrosion agent. The atleast one lubricity agent is selected from additives based on mono-acidsand/or fatty-acids such as HiTec and BioTec products from Afton (HiTec,BioTec and Afton are trademarks). Further, the lubricity agents arepreferably selected from compositions including polyethylene glycol,synthetic esters or hydroxyesters, fatty acids. The at least oneanti-corrosion agent is selected from corrosion inhibitor additivesincluding additives based on zinc dithiophosphates and/or calciumnitrates. Further, the anti-corrosion agent can be selected from atleast one of DCI-4A, DCI-6A, DCI-11, DCI-28, DCI-30 (DCI is a trademark). Moreover, at least one anti-corrosion agent is selected fromcorrosion inhibitors including organic amines, for example ethanolamineor morpholine or similar basic heterocyclic compounds.

The fuel can also include other cetane enhancer (other than AN,hydrazine, hydroxylamine nitrates and octyl nitrate) such as,polyethylene glycol dinitrate (PEGDN). Further, in the fuel the PEGDNcan be included in a concentration in a range 5% to 10% by weight withrespect to alcohol.

The present embodiment of the present disclosure (similar to embodimentdisclosed in FIG. 1) is concerned with an introduction of a new additivewhich increases the efficiency of a given fuel, for example amethanol-based fuel, having a cetane enhancer and an ignition-improveradditive. The new additive provides at least one of following benefits:

-   (a) the new additive allows methanol to act a direct replacement for    many types of conventional fossil-reserve-derived fuel;-   (b) the new additive Is non-explosive, and this less hazardous in    use; and-   (c) the new additive has a potential for application in a wide range    of combustion engines.

Further, similarly the benefits of the enhanced fuel in Equation 3include:

-   (a) The method allows Ammonium Nitrate to be used as cetane enhancer    for methanol or similar alcohols, in turn allowing the fuel to be    used in existing compression-ignition engines with minimal    modifications;-   (b) The addition of water keeps an engine burning the fuel of    Equation 3 cool (due to a high latent heat of evaporation of water),    thereby decreasing a need for cooling systems, thus making the    vehicle more energy efficient;-   (c) Lower particulate emission from engines burning the enhanced    fuel of Equation 3, namely lower particulate emission than    achievable by employing other methods, for example using exhaust    filters, using Adblue spraying in exhaust systems and so forth;-   (d) Environmentally friendly, since the N-groups in AN are released    as N2 gas at the end of a burn cycle in a combustion engine; and-   (e) The enhanced fuel of Equation 2 results in a significant    reduction in cost in comparison to PEG-dinitrate-based additives,    namely AN cost approximately 1/10th of Avocet additives.

Embodiments of the present disclosure provide benefits in directinjection combustion engines, and are also capable of providing costreduction. Such cost reduction here is based on two factors:

-   (i) cost reduction due to the direct injection; and-   (ii) cost reduction due to the use of AN instead of Avocet    additives.

With respect to diesel engines, the present disclosure provides a directcompetitor to Octyl Nitrate, which is a currently favoured substance forimproving the cetane number of lower grade diesel fuels. The addition ofenough water to Ammonium Nitrate (AN) is capable of making this compoundsoluble in alcohol-based fuels, such as methanol. In turn, thispotentially allows for the use of methanol, or another alcohol, in placeof diesel fuel in current modern diesel engines. Moreover, modern dieselengines are required to be fitted with tanks containing an aqueoussolution of urea, which in turn, are optionally used as a reservoir forthe AN solution prior to injection.

Current European diesel trucks are fitted with a small urea tank, whichis beneficially optionally used as the reservoir for the AmmoniumNitrate (AN), while petrol engines do not need such an addition.

Ammonium Nitrate (AN) has a great potential to be used as an ignitionimprover -cetane enhancement for methanol (or another alcohol). Thispresent disclosure relates to the use of an aqueous solution of ammoniumnitrate as an ignition improver directly injected into the enginecylinder.

In the case of modern diesel engine, the AN solution is beneficiallyinjected in concentrations which vary in a range of 5% to 20% by weightwith respect to the alcohol. The composition of an alcohol-based fuel,preferably methanol, with the additions of the AN solution in the rangespecified and a lubricity agent could be potentially used withoutadjustment in combustion engines, leading to the concept of a versatilefuel.

If the AN is injected as described above, then the fuel can be anysubstance suitable for use, for example, as a diesel fuel. The fuel canbe used directly in spark-ignited petrol engines. For economic, safety,transport and environmental reasons, methanol has a unique capacity toprovide this capability.

The fuel is used by way of direct injection of additive into a givencylinder of a combustion engine. Modern diesel engines are required tobe fitted with tanks containing an aqueous solution of urea; this sametank is beneficially made available to contain the AN solution prior toinjection, provided that the injection line is modified to inject theadditive solution directly into the engine cylinder. Modern engines withcomputer-based fuel injection management systems, under softwarecontrol, are capable of using fuels pursuant to the present disclosure.

Embodiments of the present disclosure provide a versatile fuel, forexample a mixture of methanol, a lubricity additive and at least oneanti-corrosion agent. Such a versatile fuel is susceptible to beingemployed in spark-ignition engines. Injection of AN enables theversatile fuel to be employed in compression-ignition engines.

Optionally, the fuel is used by way of direct injection of additive intoa given cylinder of a combustion engine. Modern diesel engines arerequired to be fitted with tanks containing an aqueous solution of urea;this same tank is beneficially made available to contain the AN solutionprior to injection, provided that the injection line is modified toinject the additive solution directly into the engine cylinder. Modernengines with computer-based fuel injection management systems, undersoftware control, are capable of using fuels pursuant to the presentdisclosure.

In recent years, current environmental laws and society pressure haveplaced less emphasis on economics of fuels, and more on environmentalgains. Nevertheless, an additive that costs less, and makes an overallcombustion process in internal combustion engines more efficient willincrease economic benefits, which associated to intrinsic environmentalgains, makes alcohol once more an attractive alternative to diesel fuelfrom a commercial perspective.

Therefore, in another aspect, the present disclosure relates to methodof using a fuel for operating internal combustion engine. The combustionengine primarily includes one or more combustion chambers havingreciprocating and/or rotating elements therein which are operable togenerate mechanical work from the engine. The combustion engine alsoincludes an injection arrangement for injecting fuel into the one ormore combustion chambers. Therefore, the method pursuant to presentaspect includes operating the injection arrangement to inject analcohol-based fuel into the one or more combustion chambers, and whereinthere is injected in combination with the alcohol-based fuel at leastone ignition-improver.

The term “at least ignition-improver” broadly encompasses the cetaneenhancers and the ignition-improver additives, disclosed herein above.Therefore, the ignition-improver is at least one of: Dimethylether(DME), diethyl ether, methyl ethyl ether, Ammonium Nitrate (AN),PEG-nitrate, octyl nitrate, hydrazine, and hydroxylamine nitrate.

Further, the term “alcohol-based fuel” used herein mainly includescomponents of the fuels disclosed herein above. For example, thealcohol-based fuel contains at least one alcohol, water, at least onelubricity agent and at least one anti-corrosion agent. Moreover, thelubricity agent is at least one of polyethylene glycol, syntheticesters, and fatty acids; and the anti-corrosion agent contains organicamines.

In an embodiment, the method of using the fuel for operating internalcombustion engine further includes pre-mixing the alcohol-based fuel andthe at least one ignition-improver using a pre-mixing arrangement.Further, the pre-mixed alcohol-based fuel and at least oneignition-improver are injected as aqueous solution into one or moreengine cylinders by a common injector. Alternatively, the method ofusing the fuel for operating internal combustion engine includesinjecting the alcohol-based fuel and the at least one ignition-improverinto one or more engine cylinders by separate injectors.

The method also includes controlling an amount of the at least oneignition-improver injected into the one or more combustion chambersrelative to an amount of alcohol-based fuel injected therein by using acontrol arrangement. The controlling of the amount of the at least oneignition-improver is based on one or more measured parameters associatedwith the combustion engine. In an example, the control arrangementincludes a computing-device-based controller operable to executecomputer program instructions, including one or more sensors fordynamically controlling the fluid pumps as a function of one or moreengine parameters, for example as a function of at least one of enginetemperature, engine load, ambient temperature, fuel-type, acceleratorpedal position.

The nozzles for injectors in combustion engines pursuant to the presentdisclosure are beneficially manufactured from spark-eroded Hastelloy-N,sintered Silicon Carbide, sintered metals, sintered ceramic materialssuch as Carborundum, and similar. Sintered materials are of advantage inthat they can be spatially formed by a moulding process prior to theirsintering.

According to an embodiment of the present disclosure, there is provideda retrofit kit including nozzles, fluid pumps and piping for providingadditive and fuel separately for injection into cylinders of acombustion engine. Otherwise, the retrofit kit can include a singlenozzle (or the common injector) associated with the pre-mixingarrangement (such as a pre-mixing container).

In the present disclosure, Dimethylether and Ammonium nitrate (AN) arebeneficially employed, for example with reference to FIG. 4 and FIG. 5,respectively as ignition-improver and as a directly-injected cetaneimprover. For example, as shown in FIG. 4, the alcohol-based fuelincludes the alcohol (such as methanol), the ignition-improver additive(such as DME), water, the lubricity agent and the anti-corrosion whichare premixed (for in the pre-mixing container) and injected in the sparkignition engine by the single nozzle (or the common injector). However,in the shown in FIG. 5, the alcohol-based fuel and an aqueous solutionof AN is beneficially directly injected into a cylinder of a combustionengine to function as the cetane enhancer. Specifically, in such anengine (compression-ignition), two injectors are employed for eachcylinder of the combustion engine. Thus, use of aqueous AN injection asa cetane enhancer enables fuel neutral operation to be achieved, namelyapplicable for both diesel fuel and alcohol-based fuels.

The above embodiment relates to combustion engines which are operable touse an aqueous solution of Ammonium Nitrate as an ignition improverdirectly injected into the engine cylinder, for example via a dedicatednozzle for the ignition improver and/or when the ignition improver ispre-mixed into fuel which is injected into the engine cylinder. Further,the method allows Dimethylether and/or Ammonium Nitrate to be used as anignition improver for methanol-based or similar alcohol-based fuels, inturn allowing the fuels to be used in existing compression ignitionengines with minimum modifications; or by exchanging injector nozzles ofcylinders of a compression ignition engine with an alternative type,which has multiple injection nozzles, namely one nozzle for thealcohol-based fuel and another nozzle for the Ammonium Nitrate.

Modifications to embodiments of the disclosure described in theforegoing are possible without departing from the scope of thedisclosure as defined by the accompanying claims. Expressions such as“including”, “comprising”, “incorporating”, “consisting of, “have”, “is”used to describe and claim the present disclosure are intended to beconstrued in a non-exclusive manner, namely allowing for items,components or elements not explicitly described also to be present.Reference to the singular is also to be construed to relate to theplural. Numerals included within parentheses in the accompanying claimsare intended to assist understanding of the claims and should not beconstrued in any way to limit subject matter claimed by these claims.

REFERENCE LITERATURE

-   [1] Gaouyer, J. P.: “What has happened in Europe in the Biofuels    Domain over the last two years?” Proceedings 2nd European Motor    Biofuels Forum, Graz, p. 37-41, 1996.

1. A fuel for use in internal combustion engines, wherein the fuelincludes a mixture of at least one alcohol, water and ammonium nitrate(AN) as a cetane enhancer, wherein water is included in a quantity whichrenders the ammonium nitrate dissolved in the at least one alcohol,wherein the at least one alcohol includes methanol.
 2. The fuel asclaimed in claim 1, wherein the AN and water solution is mixed inalcohol to allow the AN/alcohol ratio in be in a range of 0.5% to 20% byweight with respect tot he aclohol, wherein the AN is included in aconcentration having a range of 1% to 5% by weight with respect to thealcohol. 3-5. (canceled)
 6. The fuel as claimed in claim 1, the fuelfurther contains polyethylene glycol dinitrate (PEGDN), wherein thePEGDN is included in a concentration in a range of 5% to 10% by weightwith respect to alcohol.
 7. (canceled)
 8. The fuel as claimed in claim1, wherein the fuel further contains at least one ignition-improveradditive, at least one lubricity agent and at least one anti-corrosionagent, wherein the ignition-improver additive is at least one ofdimethylether (DME), diethyl ether or methyl ethyl ether, wherein theDME is included in a concentration in a range of 0.1% to 3% by weightwith respect to the alcohol. 9-11. (canceled)
 12. The fuel as claimed inclaim 8, wherein the lubricity agent is at least one of polyethyleneglycol, synthetic esters, and fatty acids, wherein the anti-corrosionagent contains organic amines.
 13. (canceled)
 14. A method of producinga fuel, wherein the method includes: (i) Mixing at least one alcohol,dimethylether (DME) and Ammonium Nitrate (AN); and (ii) During mixing in(i), adding water in a quantity which renders the AN dissolved in the atleast one alcohol, wherein the at least one alcohol includes methanol.15. (canceled)
 16. The method as claimed in claims 14, wherein the AN isincluded in a concentration having a range of 0.5% to 10% by weight withrespect to the alcohol, wherein the AN in included in a concentrationhaving a range of 1% to 5% by weight with respect to the alcohol. 17.(canceled)
 18. The method as claimed in claim 14, wherein the DME isincluded in a concentration in a range of 0.1% to 5% by weight withrespect to the alcohol, wherein the DME is included in a concentrationin a range of 0.1% to 3% by weight with respect to the alcohol. 19.(canceled)
 20. The method as claimed in claim 14, further includesadding at least one lubricity agent and at least one anti-corrosionagent, wherein the anti-corrosion agent includes organic amines.
 21. Themethod as claimed in claim 20, wherein the lubricity agent is at leastone of polyethylene glycol, synthetic esters, and fatty acids. 22.(canceled)
 23. The method as claimed in claim 20, further includesadding polyethylene glycol dinitrate (PEGDN), wherein the PEGDN isincluded in a concentration in a range of 5% to 10% by weight withrespect to alcohol.
 24. (canceled)
 25. A method of using a fuel foroperating an internal combustion engine, wherein the combustion engineincluding one or more combustion chambers having reciprocating and/orrotating elements therein which are operable to generate mechanical workfrom the engine, and an injection arrangement for injecting fuel intothe one or more combustion chambers, wherein the method includes: (a)operating the injection arrangement to inject an alcohol-based fuel intothe one or more combustion chambers, and wherein there is injected incombination with the alcohol-based fuel at least one ignition-improver.26. The method as claimed in claim 25, further includes pre-mixing thealcohol-based fuel and the at least one ignition-improver using apre-mixing arrangement.
 27. The method as claimed in claim 25, furtherincludes injecting the pre-mixed alcohol-based fuel and at least oneignition-improver as aqueous solution into one or more engine cylindersby a common injector.
 28. The method as claimed in claim 25, furtherincludes injecting the alcohol-based fuel and the at least oneignition-improver into one or more engine cylinders by separateinjectors.
 29. The method as claimed in claim 25, further includescontrolling an amount of the at least one ignition-improver injectedinto the one or more combustion chambers relative to an amount ofalcohol-based fuel injected therein by using a control arrangement. 30.The method as claimed in claim 25, wherein the controlling of the amountof the at least one ignition-improver is based on one or more measuredparameters associated with the combustion engine.
 31. The method asclaimed in claim 25, wherein the alcohol-based fuel contains at leastone alcohol, water, at least one lubricity agent and at least oneanti-corrosion agent, wherein the anti-corrosion agent contains organicamines.
 32. The method as claimed in claim 31, wherein the lubricityagent is at least one of polyethylene glycol, synthetic esters, andfatty acids.
 33. (canceled)
 34. The method as claimed in claim 25,wherein the ignition-improver is at least one of: Dimethylether (DME),diethyl ether, methyl ethyl ether, Ammonium Nitrate (AN), PEG-nitrate,octyl nitrate, hydrazine, and hydroxylamine nitrate.